The gravitational waves from the first-order phase transition with a dimension-six operator

TL;DR

This paper explores gravitational waves generated by first-order phase transitions in an extended standard model with a dimension-six operator, highlighting how running RG scales influence GW signals and detection prospects.

Contribution

It provides a unified description of slow and fast first-order phase transitions and analyzes the impact of running RG scales on GW spectrum predictions.

Findings

Running RG scales can amplify GW peak amplitude by an order of magnitude.

Peak frequency shifts to lower values with running RG scales.

Detection prospects depend on the sextic term's lower cutoff value.

Abstract

We investigate in details the gravitational wave (GW) from the first-order phase transition (PT) in the extended standard model of particle physics with a dimension-six operator, which is capable of exhibiting the recently discovered slow first-order PT in addition to the usually studied fast first-order PT. To simplify the discussion, it is sufficient to work with an example of a toy model with the sextic term, and we propose an unified description for both slow and fast first-order PTs. We next study the full one-loop effective potential of the model with fixed/running renormalization-group (RG) scales. Compared to the prediction of GW energy density spectrum from the fixed RG scale, we find that the presence of running RG scale could amplify the peak amplitude by amount of one order of magnitude while shift the peak frequency to the lower frequency regime, and the promising regime of detection within the sensitivity ranges of various space-based GW detectors shrinks down to a lower cut-off value of the sextic term rather than the previous expectation.